This invention relates to pigments. More particularly it relates to the converting of crude phthalocyanine pigments to pigmentary form. As used herein, the term "crude pigment" defines a colorant that has a much larger particle size than does its pigment grade; for example, the particle size of the crude grade of phthalocyanine is generally about 40 to 50 microns or larger, whereas the particle size of its pigmentary grade is generally about 0.01 to 1 micron.
There are many known methods for conditioning crude pigments, such as dry grinding the crude phthalocyanine in the presence of a grinding aid, such as an alkali metal halide, carbonate, sulfate, or phosphate; sugar; urea; calcium oxide; or the like. Other methods include grinding the crude phthalocyanine in the absence of a grinding aid, then admixing it with an organic solvent; admixing the finely-divided crude material with sulfuric acid and a copper phthalocyanine derivative; admixing the finely-divided crude material with an organic or aqueous organic medium and a copper phthalocyanine derivative; or admixing the finely-divided crude phthalocyanine with an aqueous medium containing a surfactant. Another method of conditioning a crude phthalocyanine is to grind it in the presence of a solvent and a sulfonated phthalocyanine amine derivative.